DESCRIPTION: This proposal, the competitive renewal for the principal investigator's current grant (EY07760) uses psychophysical methods to achieve the following research objectives: a) to understand the nature and, where possible, the neuroanatomical loci of processes involved in visual perception of objects and events, with particular emphasis on visual information provided by stereopsis and motion; b) to examine the influence of knowledge and/or expectations on registration and integration of object/motion information; c) to learn how efficiently visual information is deployed under conditions where that information must be recalled from memory; and d) to distinguish conscious from unconscious processes in the analysis of that visual information, particularly as unconscious processing relates to binocular rivalry. Specific experiments address the following questions: 1. How effectively can texture borders and contrast modulated, "non-Fourier" contours support stereoscopic processing? 2. To what extent does knowledge about object identity influence motion perception? 3. How accurate is human memory for visual motion? 4. How refined is the analysis of motion information relative to neural processing at the site at which binocular suppression interrupts vision? Specific methods include forced-choice measurement of stereoscopic discrimination performance and discrimination of biological motion sequences, tracking of periods of dominance and suppression in binocular rivalry, induction of motion priming under conditions of rivalry, measurement of direction and/or motion coherence discrimination under conditions where observers must remember motion information for extended durations. Results from these experiments, besides providing information on the nature and sequence of processing underlying binocular vision and motion perception, will bear importantly on contemporary theories of motion perception and may point the way to physiological studies of the neural concomitants of motion and binocular vision (including their disorders).